The bearded rocker took a tumble as he was stepping off the band's tour bus in Lubbock and was too injured to go on with the show, according to TMZ.com.
The 66-year-old was taken to a nearby hospital for treatment.
The Lubbock show has been rescheduled for 29 May (16).
It's not the first time Hill's injuries have forced ZZ Top to scrap a show - a tour bus injury forced him off the road in 2014.
The group had to axe a tour with Jeff Beck after the bass player suffered a nasty hip injury.
Hill returned to the stage in January, 2015.
ZZ Top are scheduled to perform in Shawnee, Oklahoma on Friday night (15Apr16), and will return to Texas on Saturday (16Apr16) for a set at the Chilifest in Snook. It is not clear if Hill will join his bandmates onstage.